Reliability of Using a Handheld Tablet and Application to Measure Lower
Extremity Alignment Angles

King D.L, Belyea B.C. J Sport Rehabil; 2014; ahead
of print

Take Home
Message: A tablet application is a promising, reliable tool to capture
objective landing kinematics. Intra-rater reliability is good to excellent with
an average of 6 trials. Inter-rater reliability is fair to excellent depending
on the level of experience.

an athlete’s risk for injury is necessary to tailor injury prevention plans for
an athlete. To assess risk for injury, medical personnel most commonly employ visual
observations of an exercise (e.g., drop vertical jump); however, errors in
visual estimations of lower extremity joint angles have been reported.
Utilizing a tablet with a movement analysis application is a more objective way
of determine joint angles during functional movement. Though, the reliability
of this new tool has not been established. Therefore, the authors measured the interrater and inter-trial
reliability among multiple researchers who evaluated 23 healthy college
students using an iPad2 and the KinesioCapture application.
The athletes performed 6 two-footed drop vertical jumps, while 1 researcher with
experience with 2-D videography captured all the trials. Then, 4 researchers (2
experienced & 2 novices) analyzed the previously captured video for the
degrees of knee and hip flexion. The researchers measured 3 of the jumps in the
sagittal plane followed by 3 jumps in the frontal plane. Inter-rater
reliability ranged from low (0.39) to excellent (0.98). Experienced raters
performed slightly better with moderate to good reliability (0.69-0.93)
compared with the novice raters (0.39-0.98). Novice and experienced raters were
more consistent at measuring joint angles at maximum knee flexion than at
initial ground contact. Averaging the trials offered better reliability than
assessing each trial separately.

is an important study since properly operating new and affordable tools are
imperative for better objective measures to determine an athlete’s risk of
injury. The authors demonstrated that the handheld tablet is a reliable tool to
measure knee and hip flexion during a drop vertical jump. The authors also
found that experience as well as multiple trials are necessary for optimal reliability.
An average of multiple trials may represent the true movement pattern, and
reduces the influence of errors (e.g., a bad movement on one trial, error in
one measurement). Future research needs to determine how much training medical
personnel requires before becoming an experienced rater. Furthermore, all of
the videos were captured by a trained individual so we may need to train
clinicians to capture an optimal video for these analyses. Future research,
will have to determine how much measurement error could be caused by changes in
how the videos are acquired. Additionally, assessing how many trials are
required for a reliable reading is necessary to apply this tool for functional
use. It will also be interesting to see how these measurements compare to
traditional motion analysis systems. While more research is needed this study shows
that measuring lower extremity movement can be reliably assessed on a tablet if
one experienced person records the video, average joint angles are calculated
across three trials, and the person doing the measurement is adequately
trained. This study is a good reminder that clinicians should check their
reliability over time and among other clinicians in a clinic to ensure

Questions for
Discussion: Do you have access to a tablet? If so, would you use the tablet to
measure landing kinematics? Do you measure/observe landing kinematics to
identify athletes at risk for knee injuries?

by: Jane McDevitt, PhD
by: Jeffrey Driban


King DL, & Belyea BC (2014). Reliability of Using a Handheld Tablet and Application to Measure Lower Extremity Alignment Angles. Journal of Sort Rehabilitation PMID: 25310432